The radiotherapy treatment is known in which a patient is treated with emission of a therapeutic radioactive ray for exposure onto an affected area of a tumor. A radiotherapy apparatus that performs the radiotherapy treatment includes a couch, an imager system that images an X-ray image of a patient laid on the couch, and a therapeutic radioactive-ray irradiating device that emits a therapeutic radioactive ray onto the patient. After the couch is positionally adjusted so that an affected area of the patient is arranged at a predetermined position based on a CT image of the patient shot previously and an X-ray image of the patient shot immediately before the radiotherapy treatment, the radiotherapy apparatus emits a therapeutic radioactive ray onto the affected area. In the radiotherapy treatment, it is desired to more accurately arrange the affected area of the patient at a predetermined position.
The Japanese Patent Publication No. 4159227 discloses a patient-position displacement measurement apparatus that improves positioning accuracy by directly measuring the position of an irradiation target in a soft-part tissue that is difficult to discriminate. As for the patient-position displacement measurement apparatus, a patient-position displacement measurement apparatus for measuring a displacement amount of a patient position from a target position includes storage means that stores all optical flows in which the motion of pixels on an image is represented by vectors within an expected range of a patient-position displacement amount previously calculated, measuring means that measures actual optical flows, and matching means that finds a position displacement amount of the patient by comparing a stored optical flow stored in the storage means and the measured optical flow actually measured.
The Japanese Patent Publication No. 3825384 discloses a radiotherapy apparatus that can easily position an irradiation target of a radioactive ray within a radioactive-ray irradiating range. The radiotherapy apparatus includes a radioactive-ray generating device that emits a radioactive ray and a laser light beam onto a same axis, at least three body surface markings indicating a position where the center axis of the radioactive ray is incident to a patient and having an azimuth set with respect to an irradiation target, a guide that arc-moves the radioactive-ray generating device about an isocenter along an orbit of a radius of a predetermined distance so that irradiation axes where the radioactive ray and the laser light beam are emitted onto the same axis cross at one point, a supporting member that rotate the guide about a tilt axis crosses a rotation axis of an arc-movement of the radioactive-ray generating device along the guide at the isocenter, a movable member that moves the radioactive-ray generating device along the guide, a slide board that moves the patient so that the body surface markings coincide with laser light beams projected from respective azimuths set by using the movable member, a detector that detects information of a radioscopic image in a range including the isocenter and the irradiation target of the radioactive ray arranged nearby, an analyzing device that computes a relative position relation between a position of the isocenter and a position of the irradiation target based on information about a plurality of the radioscopic images detected by the detector at the respective azimuths and information about the azimuths at which the radioscopic images are detected with respect to the isocenter, and a control device that causes the radioactive-ray generating device to move based on the relative position relation.
The Japanese Patent Publication No. 4310319 discloses a radiotherapy apparatus control apparatus that more accurately matches a predetermined position of a sample subject at a predetermined position of a radiotherapy apparatus. The radiotherapy apparatus control apparatus controls a radiotherapy apparatus that includes a therapeutic radioactive-ray irradiating device that irradiates a therapeutic radioactive ray, an imager that generates an imager image of the sample subject with a radioactive ray passing through the sample subject, and a driving device that moves a couch where the sample subject is arranged toward the therapeutic radioactive-ray irradiating device. The radiotherapy apparatus control apparatus includes a three-dimensional data generating part that generates a three-dimensional data of the sample subject based on a radioscopic image imaged by the imager, a two-dimensional image generating part that generates a two-dimensional image based on the three-dimensional data, a radioscopic-image imaging part that images an imaged imager image of the sample subject by using the imager, an affected-area position control part that determines, based on a position where a feature point included in the sample subject is reflected on the imaged imager image and a position where the feature point is reflected on the two-dimensional image, whether a relative position of the couch with respect to the therapeutic radioactive-ray irradiating device is appropriate, and a reference-image generating part that generates a reference imager image based on the imaged imager image, and the affected-area position control part further determines, based on a position where the feature point is reflected on another imaged imager image imaged by the imager and a position where the feature point is reflected on the reference imager image, whether the relative position of the couch with respect to the therapeutic radioactive-ray irradiating device is appropriate.